The term mobile unit covers both a self-propelled assembly such as a wheeled vehicle of the truck type, and an assembly that itself towed, such as a trailer, a wagon, or indeed an assembly suitable for mounting on a trailer or on the chassis of a vehicle.
There exists trucks, known as jetter-trucks, that can be used for applying both a water-jet and suction to sewer networks, i.e. for enabling the deposits that accumulate in manholes and the adjacent channels to be removed by means of a cleaner hose having a cleaner head that delivers a high-pressure water-jet, and by means of a suction hose for sucking up the liquid residue and sludge.
It will be understood that equipment of that type must enable the operator, who remains close to the manhole situated in a roadway, to place the cleaner hose with the cleaner head at its end in the manhole in the desired location(s), to hold it in position throughout the high-pressure cleaning operation while causing water to be delivered at high pressure, and then to raise it back onto the truck. Thereafter, the operator needs to perform the same positioning, control, retention, and raising operations using the suction hose.
From the above, it can thus be understood that the operator needs to perform a large amount of handling while not having a good view of the position inside the manhole, and thus while not guaranteeing that cleaning will be performed properly and that no zones will be left unwashed and/or with debris that has not been sucked up.
Furthermore, in particular when raising the hoses, and more particularly the cleaner hose, splashing can arise outside the manhole that, combined with possible dirtying of the hoses, can lead to situations and to handling difficulties that can sometimes be most uncomfortable for the operator.
Document DE 102 46 041 discloses a cleaning vehicle having an arm mounted on the vehicle that is movable relative to the vehicle to swivel about a vertical axis and to move in horizontal translation, the arm carrying a suction hose and a cleaner hose.
Document EP 0 698 696 also discloses a cleaning vehicle fitted with a high-pressure cleaner hose and a suction hose mounted on a horizontal-swiveling telescopic boom.
Nevertheless, it is desirable to achieve greater accuracy in the positioning of the suction and cleaner hoses, in particular over the manhole, and in particular close to the manhole, and in the manhole, both vertically (height/depth) and in a radial direction about a vertical axis running along the manhole.